In depth

Jun 16, 2008

HiPerNano rises to the challenge

Manufacturers and end users in the field of nano-enhanced materials for extreme environments gathered in London last month for an industry awareness day hosted by the UK's Nanotechnology Knowledge Transfer Network (KTN). Martin Kemp looks at the challenges facing the sector and reveals some of the developments in the pipeline, including the launch of a new sector focus group dubbed HiPerNano.

Setting the scene
Nano-enhanced materials are rapidly emerging worldwide in every category imaginable. Key areas include paints and coatings, with products such as the clear, scratch resistant topcoat used on Mercedes Benz cars as well as coatings for alloy wheels. Novel silica-based coatings are being developed with barrier and anti-fouling properties. Hard coatings applied by physical and chemical vapour deposition have been available for some time, and here improvements are being realized through nanostructuring.

Enhancing polymers by adding low-tech nano-additives, such as clay, carbon black and silica, is by no means new. Toyota led the way in the car industry, and GM has recently used a reinforced polymer on the Chevrolet Impala. The German car industry is adding fillers to provide EMI shielding properties and conductivity in plastic fuel components to mitigate sparking. Tyres make use of ceria nanoparticles to enhance durability and a major manufacturer of polycarbonate headlamp covers is incorporating a nanocoating to enhance scratch resistance.

The addition of advanced nanofillers into resins is one of the most exciting areas of composites development. Sporting goods that feature this technology are already available, such as tennis racquets from manufacturers such as Babolat, ice hockey sticks from Montreal and a racing yacht from Baltic. This, however, is the tip of the composites iceberg, and large-scale structures are likely to be next in line to hit the market.

Composites traditionally have excellent tensile properties, but low compression and impact properties. Since nanoparticles are so small, they can reinforce the resin-rich areas between fibre bundles, which otherwise exhibit on a microscale the lower properties of the resin. It is likely that all kinds of additives at the nanoscale will also be incorporated, such as fire retardants. "Smart" properties, such as self-healing, may also become possible.

Processing possibilities
Powder metallurgy offers great and obvious potential for nano-enhancement, since nanomaterials can be readily incorporated. Fawad Inam of Nanoforce, one of the UK Technology Strategy Board's nanotechnology facilities based at Queen Mary College, is working on the manufacture of electrically conducting ceramics. As Inam explained at the event, spark plasma sintering is a new process that can produce materials from powder, such as alumina reinforced with containing carbon nanotubes. This opens the door to making high-performance ceramic material that is electrically and thermally conducting. Potential applications include spacecraft heat shields, armour, bio-inert ceramics and functionally graded materials.

Another interesting application is rapid prototyping, or additive layer manufacturing, as discussed by Benjamin Farmer of Airbus UK, who speculated that we could soon see complex components manufactured to net shape in a high-performance material through nano-enhancement. This is of potentially great economic benefit in an industry where 90% of material is currently machined away. Performance fibres are a rapidly growing market, and research by Alan Windle at Cambridge University on a patented process for continuous production of carbon nanotube fibres promises ultra-high-performance fibres for use in body armour and lightweight electrical cables.

Big challenges
Extreme environments, such as corrosion, friction, wear, high-rate impact and erosion are experienced in many of the market sectors addressed at the meeting.

Len Pinder of E.ON Engineering explained that the conventional power generation industry, for example, must operate the new generation of low carbon-emission boilers at higher temperatures and pressures. This requires materials of higher strength than low carbon steel, but combined with corrosion resistance and weldability.

Emerging biomass fuels pose an additional challenge due to high chlorine and potassium content. Here, nano-enhanced paints and coatings could offer a helping hand.

Wind farms, which are gaining in popularity, experience extremely high bearing loads in gearbox components, and in offshore applications, corrosion from salt-laden air. Chris Walker of Diamond Hard Surfaces described the optimisation of hard coatings using a new diamond-like coating process.

Aerospace is an area of significant challenges, and Benjamin Farmer of Airbus UK outlined the use of nano-enhanced materials to mitigate lightning strike through enhanced electrical conductivity in composites without the weight penalty of metallic mesh.

Team effort
The overwhelming response from industry confirmed that we had touched a nerve in the choice of a highly relevant theme. To capture the momentum of the day, we're now in the process of setting up a sector focus group based on multisectoral materials challenges – dubbed HiPerNano.

The aim of the group is to define an industry-led agenda to steer the Nanotechnology KTN's activities within the high-performance engineering sector. The initiative will be led by a steering group who will develop the template and determine priority areas. Each industry sector has a different set of priorities with respect to nanotechnology, and the sector focus group is the "eyes and ears" of the Nanotechnology KTN in that market space.

Membership of the HiPerNano mailing list is open to all and members will receive updates on events and activities, such as the forthcoming online seminar "EU Framework Programme 7 – How to Get Involved" on 18 July at 10.30 a.m.

About the author

Martin Kemp is theme manager of Materials for the Nanotechnology KTN – a Technology Strategy Board initiative managed by the Centre for Process Innovation, UK. Martin.kemp@nanoktn.com

For further details on HiPerNano, future activities, and to find out how you can get involved, e-mail natasha.taylor@nanoktn.com or call +44 (0)7826 902 204.